This invention relates to tiltable mountings for TV cameras or the like including cinematograph and video cameras.
Such mountings should tilt smoothly and easily and should be counterbalanced so that they remain static without additional support wherever they are placed in the range of tilt angle provided. The counterbalance mechanisms must be readily adjustable to cater for cameras of different weights and which have centres of gravity at different heights above the support.
UK Patent Specification No. 2189042 discloses such a tiltable mounting comprising a base, a support member for supporting an article thereon, the support member being tiltable about an axis on the base for tilting about each side of a neutral position in which the center of gravity is above the axis, guides mounted at a pivot on the support member which is offset relative to the axis, guideways pivotally mounted on the base and slidable in the guides, the guideways intersecting the axis when the support member is at the neutral position, and spring means located on the guideways such that upon tilting of the support member from its neutral position, the spring means is deflected and produces a reaction on the support member which is equal to the out of balance moment of the tilted center of gravity. To cater for cameras of different weights and with centres of gravity at different locations above the support, the guides have adjusting means mounted on the base to preload said spring means in relation to the weight and position of the centre of gravity of the article.
This invention provides a tiltable mounting for a TV camera or the like comprising a base, a camera support mounted on the base to tilt about a first horizontal axis to either side of a neutral, upright position, and a counterbalancing mechanism for holding the support with a payload upright or in any rotational position to which it is moved from said upright position, the counterbalancing mechanism comprising an elongate guideway having one end coupled to the support at an eccentric location to said first horizontal axis, a guide with which the guideway is slidably engaged pivotally mounted on the base about a further horizontal axis spaced from said first axis such that tilting movement of the mounting about the first axis from the neutral position causes the guideway to slide with respect to the guide, preloaded spring means acting between the guide and a stop on the guideway to resist movement of the guideway with respect to the guide with tilting of the support from the neutral position to provide said counterbalancing force and a mounting for the guide providing adjustment along a line intersecting said first and further axes for moving the guide along the guideway and thereby adjusting the preload of said spring means, wherein the guide is mounted for linear movement by a spaced pair of links pivotally connected to the guide and to the base at respective spaced locations.
Preferably said first and further axes are spaced horizontally and said guide is mounted on said links for movement along a horizontal line intersecting said first and further axes.
In either of the above arrangements the means for adjusting the guide linearly may comprise a shaft mounted for rotation on the base about an axis extending along said line passing through the first and further axes, the shaft having a screw threaded portion which engages in a screw threaded bore in a part of the guide so that rotation of the shaft adjusts the position of the guide.
More specifically the guide has a screw threaded socket in which the screw threaded portion of the shaft engages.
In any of the above arrangements the elongate guide may have a stop for said spring means at the end remote from the end eccentrically connected to the tiltable mounting and the spring means act between the stop and guide.
Also in any of the above arrangements two or more guideways may be connected side by side to the tiltable mounting and engage in two or more guides connected together to pivot about said further axis.